The present invention relates to a multi-compartment syringe and more particularly to a pre-filled single barreled multi-compartment syringe that stores at least two substances in separate compartments until ready to be mixed just prior to use.
The multi-compartment syringe according to the present invention is a single barreled syringe that may be configured to store two or more components of a medicament or other formulation separately in hermetically sealed compartments until just prior to use.
When ready to mix the contents of the pre-filled syringe, the seal(s) partitioning the compartments can be easily unsealed, establishing flow communication between the compartments so that the contents of each compartment can be mixed to form the medicament.
A two-compartment syringe device according to one embodiment of the present invention includes a syringe body having an opening at each of its top and bottom ends and a shoulder located between the top and the bottom ends. The shoulder delineates the syringe body into a top compartment and a bottom compartment.
A base ridge located between the shoulder and the bottom end of the syringe body further defines the syringe body into a bottom-compartment sidewall portion and a base-skirt portion. The bottom-compartment sidewall portion is between the shoulder and the base ridge and the base-skirt portion is between the base ridge and the bottom end of the syringe body. The bottom-compartment sidewall portion has a larger diameter than the top-compartment sidewall portion and the base-skirt portion has a larger diameter than the bottom-compartment sidewall portion.
A plunger having a shaft, a distal end, a proximal end, and a plunger at the distal end is provided within the syringe body. The plunger head is configured and adapted to form a slidable hermetic seal when it engages the top-compartment sidewall. The plunger is axially translatable between a first position where the plunger head is slidably sealingly engaged within the top-compartment sidewall, dividing the syringe body into a top compartment and a bottom compartment, and a second position where the plunger head is disengaged from the top-compartment sidewall portion establishing a flow communication between the top and bottom compartments.
A bung having an aperture is also provided. The plunger shaft is slidably disposed within the aperture of the bung so that the bung is slidable along the plunger shaft between a sealed position, hermetically sealing the bottom-end opening, and an unsealed position where the bottom-end opening is not sealed. When the bung is in its sealed position, it is substantially positioned within the base-skirt portion of the syringe body and the plunger can be axially translated between its first position and the second position without dislodging the bung from the base-skirt portion. To enable the translation of the plunger without dislodging the bung, the bung may be configured and adapted so that the friction between the bung and the syringe body is greater than the friction between the bung and the plunger shaft.
The syringe is assembled and filled, according to one method, by first orienting the body with the two-compartment embodiment of the syringe in an upright position with its top-end opening pointing upwardly. The plunger is then inserted into the syringe body, plunger-head portion first, until the plunger head engages the top-compartment sidewall. This forms a hermetic seal at the bottom of the top compartment near the shoulder portion. The top compartment is then filled with a first component of a medicament, preferably a liquid, through the top-end opening and sealed with a suitable top sealing member or assembly. To prevent any degradation of the first component from prolonged exposure to air during storage, the top compartment may be sized to fill completely with the first component liquid, minimizing or eliminating any air pockets inside the top compartment. Alternatively, any unfilled space in the top compartment may be filled with a material, such as nitrogen gas for example, which is inert with the first component.
Where the first component of a medicament is a liquid, the top compartment may be filled by inserting the plunger completely to the end of the top compartment, immersing the open top end in the liquid, then drawing the liquid into the top compartment by pulling the plunger back to its sealed position between the compartments.
Next, the syringe device may be turned 180 degrees, with the sealed top end oriented downwardly, so that the bottom-end opening is facing up. The bottom compartment is filled with a second component of the medicament through the bottom-end opening and sealed with the bung. The second component may be a liquid or a powdered solid substance. In this embodiment where a bung seals the bottom opening, the second component may be placed in the bottom compartment in a hydrated form and dried using a lyophilization process. Before the lyophilization process begins, the bung is brought close to the base-skirt portion so that it almost fits into the base-skirt portion and the substantial portion of the bung remains outside the base-skirt portion. The vacuum created in the bottom compartment during the lyophilization process pulls the bung completely into the base-skirt portion sealing the bottom-end opening.
Alternatively, the bottom opening of the syringe body may be configured and adapted to be sealed using a bottom closure member that can be screwed onto the syringe body""s bottom-end opening.
A syringe device having three compartments may also be provided for separately storing three components of a medicament for storage until ready for use. In this embodiment the syringe device has an additional compartment situated between the top and bottom compartments. As with the two-compartment embodiment, each compartment section has progressively larger diameter where the top compartment closest to the top-end opening has the smallest diameter and the bottom compartment has the largest diameter. The hermetic seal between the top and the middle compartment is formed by the plunger head and the top-compartment sidewall. The hermetic seal between the middle compartment and the bottom compartment is formed by an additional bung that sealingly engages the portion of the syringe body between the middle compartment and the bottom compartment where the diameter of the syringe body changes. The present invention also includes the method of assembling and filling such a syringe device.
The invention will now be described in more detail with references to two and three-compartment embodiments of the syringe device of the invention. It would be appreciated by those skilled in the art that the same principle is also applicable to syringe devices having more than three compartments.